1. Field of the Invention
The present invention relates to an antenna setting apparatus, particularly to an antenna setting apparatus at a receiving station.
2. Description of the Background Art
Japanese Patent Laying-Open No. 2004-260308 discloses a channel selection apparatus in which a plurality of tuners are controlled based on reset information stored in a storage circuit to select a desired channel, including: a determination signal output circuit provided for each tuner, the determination signal output circuit outputting a determination signal indicating whether the channel selected by the tuner is a used channel or an unused channel; and a control circuit that uses the plurality of tuners simultaneously to sequentially set a selected channel so that no channel is assigned to more than one tuner and produces reset information using a determination signal for a set channel and a tuner setting information for selecting a channel indicated by the determination signal to be a used channel.
The above invention can decrease the time required for auto presetting using a plurality of tuners simultaneously.
Japanese Patent Laying-Open No. 05-328244 discloses a channel selection apparatus for a television set characterized in that a channel is selected for the television set by scaling down videos from a plurality of stations and displaying them simultaneously on one screen that is divided into sub-screens, and displaying a cursor on the screen which can be moved to select the station of a video pointed to by a cursor.
This invention allows video contents from multiple stations can be viewed simultaneously, facilitating channel selection.
Japanese Patent Laying-Open No. 2004-112573 discloses an adaptive array radio communication apparatus with a plurality of antennas including: a determination circuit determining the reception level of a plurality of sequences of signals received by the respective antennas; a display device displaying the reception level of the sequences of signals for which determination has been made; and a reception level adjustment device for adjusting the reception level of the sequences of signals based on manual operation by a user. This invention allows a user to easily adjust the antenna reception level even in an adaptive array radio communication apparatus with a plurality of antennas.
Unfortunately, the inventions disclosed in Japanese Patent Laying-Open Nos. 2004-260308, 05-328244 and 2004-112573 may have difficulty receiving a user's desired broadcasts. For example, Advanced Television Systems Committee (ATSC) digital broadcasting and National Television Standards Committee (NTSC) analog broadcasting are provided in North America. Broadcast stations for such broadcasting are distributed across the United States. A conventional antenna (Yagi antenna, for example) can only receive broadcasts from those of the broadcast stations that are located in a particular direction. FIG. 5 is a schematic view illustrating this problem. For example, when the antenna of a user's home 70 may be oriented to area A, only broadcasts from area A can be received at user's home 70. Broadcasts from areas B and C cannot be received.
The smart antenna was developed to solve this problem. A smart antenna allows the direction to receive a broadcast to be arbitrarily set. A smart antenna allows a user to receive broadcasts from any direction. Unfortunately, a smart antenna is very difficult for the user to adjust (particularly to provide excellent image quality). FIG. 6 is a schematic view illustrating how this problem occurs. Typically, the direction of a smart antenna to receive an electric wave is set to the direction providing the highest intensity of a received signal (such setting itself is difficult for a user without specialist knowledge). However, a wave from broadcast station 72 reflected by a building 74, for example, may provide a higher intensity than that by a wave directly received from the station. In such a situation, the received image may not be optimal if the direction of a smart antenna to receive an electric wave is set to the direction providing the highest intensity of a signal. The necessity of taking that into consideration is one of the reasons why it is so difficult for the user to adjust the smart antenna. Due to this and other problems, antenna manufacturers considered the adjustment of the direction to receive a broadcast as outside the scope of user operation. Still, it is a great nuisance for the user to ask a specialist to adjust their antenna each time a path for receiving electric waves is changed (for example, a new broadcast station is established or an old one is decommnissioned, or a new building appears). This problem does not depend on whether analog or digital broadcasting is concerned because, for analog broadcasting, the image quality is dependent on the quality of an electric wave received and, for digital broadcasting, block noise may prevent a received signal from being decoded by the decoder.